Data Communication System: Overview Pontiac Torrent I

Data Communication Schematic Icons

Data Communication Schematic Icons Icon Icon Definition CAUTION: When performing service on or near the SIR components or the SIR wiring, the SIR system must be disabled. Refer to SIR DISABLING AND ENABLING. Failure to observe the correct procedure could cause deployment of the SIR components, personal injury or unnecessary SIR system repairs. IMPORTANT: Twisted-pair wires provide an effective shield that helps protect sensitive electronic components from electrical interference. In order to prevent electrical interference from degrading the performance of the connected components, you must maintain the proper specification when making any repairs to the twisted-pair wires shown: The wires must be twisted a minimum of 9 turns per 31 cm (12 in) as measured anywhere along the length of the wires. The outside diameter of the twisted wires must not exceed 6.0 mm (0.25 in)

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Body Control Module - C1 Connector Parts Information

Body Control Module - C1 Connector Terminal Identification

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Body Control Module - C2 Connector Parts Information

Body Control Module - C2 Connector Terminal Identification

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Body Control Module - C3 Connector Parts Information

Body Control Module - C3 Connector Terminal Identification

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Body Control Module - C4 Connector Parts Information

Body Control Module - C4 Connector Terminal Identification

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Body Control Module - C5 Connector Parts Information

Body Control Module - C5 Connector Terminal Identification

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Body Control Module - C6 Connector Parts Information

Body Control Module - C6 Connector Terminal Identification

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Body Control Module - C7 Connector Parts Information

Body Control Module - C7 Connector Terminal Identification

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Data Link Connector (DLC) Connector Parts Information

Data Link Connector (DLC) Connector Terminal Identification

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SP200 Connector Parts Information

SP200 Connector Terminal Identification

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Terminator Resistor (Except MH6) Connector Parts Information

Terminator Resistor (Except MH6) Connector Terminal Identification

Circuit/System Description

The internal fault detection is handled inside the control module. No external circuits are involved.

The internal fault detection is handled inside the control module. No external circuits are involved.

The internal fault detection is handled inside the control module. No external circuits are involved.

The high speed GMLAN serial data circuits are high speed serial data buses used to communicate information between the control modules. Typical data transmission speeds must be high enough to ensure that a required real-time response is maintained. The high speed GMLAN serial data circuits also connect directly to the data link connector (DLC).

Modules connected to the high and low speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.

The body control module (BCM) activates the serial data communication enable circuit by applying voltage when the ignition key is in ACC, ON or START. The serial data communication enable circuit wakes up the electronic brake control module (EBCM), all wheel drive module and the electronic power steering control module if equipped for buss communication.

Modules connected to the CAN bus serial data circuits are high speed serial data modules that monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.

The electronic brake control module (EBCM) activates the other modules connected to the CAN serial data circuits by applying voltage when the ignition key is in ACC, ON or START. The EBCM, Yaw Rate Sensor and the Steering Angle Sensor are the only modules connected to the CAN bus serial data circuits. For more information on CAN bus serial data refer to Data Link Communications Description and Operation.

The accessory voltage circuit is a positive voltage signal to wake up the from the body control module (BCM) to the engine control module (ECM) and the transmission control module (TCM). The signal is activated in 2 ways; any time the ignition switch is in the ACC or RUN position or anytime the body control module (BCM) determines that communication is needed from the powertrain. When the ignition switch is in the ACC or RUN position, the accessory voltage circuit input from the ignition switch to the BCM is internally connected to the accessory voltage circuit output and voltage is supplied to the modules. The BCM also supplies voltage to the accessory voltage circuit when it determines that communication is necessary with the powertrain and the ignition is not in the ACC or RUN position such as during remote start.

The body control module (BCM) applies voltage to the data communication enable circuit, when the ignition key is in ACC, ON or START to enable several modules for bus communication.

Depending on option content, modules that may receive the signal are as follows

1. All wheel driver (AWD) module
2. Electronic brake control module (EBCM)
3. Power steering control module (PSCM)

Modules connected to the high GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.

Modules connected to the CAN bus serial data circuits are high speed serial data modules that monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. Each message contains the identification number of the transmitter module.

The electronic brake control module (EBCM) activates the other modules connected to the CAN serial data circuits by applying voltage when the ignition key is in ACC, ON or START. The EBCM, Yaw Rate Sensor and the Steering Angle Sensor are the only modules connected to the CAN bus serial data circuits. For more information on CAN bus serial data refer to Data Link Communications Description and Operation.

The data link connector (DLC) is a standardized 16 cavity connector. Connector design and location is dictated by an industry wide standard and is required to provide the following

1. Scan tool power battery positive voltage at terminal 16
2. Scan tool power ground at terminal 4
3. Common signal ground at terminal 5

Modules connected to the high speed GMLAN serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules when the ignition switch is in any position other than OFF. The high speed GMLAN serial data circuits must be operational for the vehicle to start due to body control module (BCM) and engine control module (ECM)/powertrain control module (PCM) communications. The theft deterrent module and ECM/PCM exchange information using the BCM as the gateway module allowing communication between the high and low speed serial data busses. The low speed GMLAN serial data circuit must also be operational for vehicle starting.

Modules connected to the low speed GMLAN serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules when the ignition switch is in any position other than OFF. The low speed GMLAN serial data circuit must be operational for the vehicle to start so the vehicle theft deterrent (VTD) module and body control module (BCM) can communicate. The low speed GMLAN serial data circuit uses SP 200 as the common connection between the modules and the data link connector (DLC).

Description and Operation

Data Link Communications Description and Operation

Body Control System Description and Operation

The body control system consists of the body control module (BCM), communications and various input and outputs. Some inputs, outputs and messages require other modules to interact with the BCM. The BCM also has discrete input and output terminals to control the vehicle's body functions. The BCM is wired to the GMLAN High speed serial data buss and the GMLAN Low speed serial data buss and acts as a gateway between them. If the BCM does not communicate the vehicle will not start due to the inability of the Engine/Powertrain Control Module (ECM/PCM) and Vehicle Theft Deterrent (VTD) Control Module to communicate without the BCM providing the gateway function.

Controller Area Network (CAN) Description

The EBCM communicates with the yaw rate sensor and the steering wheel angle sensor exclusively, when equipped. This serial data system does not communicate with the scan tool however; there are loss of communication DTCs for this system which set in the EBCM. The yaw rate sensor and the steering wheel angle sensors are in effect modules, exchanging essential information with the EBCM. For more information about these sensors refer to ABS Description and Operation.

See also:
• Master Electrical Component List